Structural arrangement of main deck on bulk cargo carrier vessels



p 1966 G. T. R. CAMPBELL ET AL 3,246,623

STRUCTURAL ARRANGEMENT OF MAIN DECK ON BULK CARGO CARRIER VESSELS Filed June 5, 1964 3 Sheets-Sheet 1 IN vsm'oRs 6.7.73. CA PBELL N. M Lnsxey A TTOPNE Yo STRUCTURAL ARRANGEMENT OF MAIN DECK ON BULK CARGO CARRIER VESSELS April 1966 e. T. R. CAMPBELL ETAL 3,246,623

Filed June 5, 1964 3 Sheets-Sheet 2 INVENTORS GTR. CAMPBELL N. V. LASKEy APT!l 1966 e. T. R. CAMPBELL ET AL 3,246,623

STRUCTURAL ARRANGEMENT OF MAIN DECK ON BULK CARGO CARRIER VESSELS Filed June 5, 1964 3 Sheets-Sheet 3 n I- I E El INVENTORS 6177i C/IMPBELL N. V. LnsKEy 4 TTO/E/YE YS whole vessel.

United States Patent 01,988 11 Claims. c1. 114-8S) This invention relates to the construction of bulk carrier vessels and particularly to the structural arrangement of the main deck of such vessels.

The invention consists essentially in eliminating the need for hatch coamings and by reducing the thickness of the main deck plating and underdeck longitudinals, whereby the deadweight of the vessel can be increased concomitant with an increase in the underdeck cubic capacity without any reduction in the water ballast capacity of the vessel. The deck of the vessel, instead of having the usual camber, slopes upwards from the sides to approximately the height of the standard hatch coamings, thereby adding considerably to the cubic capacity of the This additional cubic capacity is added to the cubic capacity of the holds of the vessel by moving upwards the under surface of the port and starboard upper water ballast tanks to the extent that their capacity is not reduced below normal requirements. Provision is also made for piping ducts under the deck of the vessel whereby piping normally laid along the hatch coamings is carried below deck thereby being given added protection against rough seas.

The object of the invention is to provide a bulk carrier vessel with added cargo capacity combined with streamlining the deck.

A further object of the invention is to provide a vessel in which hatch coamings projecting above deck level have been eliminated.

A further object of the invention is to increase the strength of the vessel, particularly at deck level while, at the same time, reducing the weight considerably.

A further object of the invention is to make provision below deck level for the piping normally laid on deck, without interfering with the cargo carrying areas of the vessel.

A further object of the invention is to provide for ventilation of the cargo holds from a central source, with individual controls at deck level.

These and other objects of the invention will be apparent from the following detailed specification and the accompanying drawings, in which:

FIG. 1 is a partial transverse section of a single deck vessel having a deck of normal camber and normal hatch coamings.

FIG. 2 is a view similar to FIG. 1 but showing a modified deck structure according to the present invention, and showing in shaded area the gain in cargo carrying capacity.

FIG. 3 is an enlarged section of the deck area of FIG. 2 showing the self-trimming features and the method of conducting the cargo oil pipes and oil stripping pipes through the deck.

FIG. 4 is an enlarged side elevation detail of the cargo hold ventilating means.

FIG. 5 is an elevation showing the ventilation opening in the side wall of the cargo hatch, taken on the line 5-5 of FIG. 4.

FIG. 6 is a partial plan view of the deck of the vessel showing the location of the ventilation controls at deck level.

FIG. 7 is a detail plan view of one of the hatch securing devices.

FIG. 8 is a side elevation of the hatch securing device taken on the line 8-8 of FIG. 7.

FIG. 9 is a detail showing the hatch locking means.

In the construction of single deck bulk cargo vessels according to Load Line Rules at present in effect, the hatch coarnings must have a depth of at least 24 inches above the level of the main or freeboard deck in the way of every deck opening.

In FIGURE 1 there is illustrated a partial transverse section of a single deck bulk carrier vessel of the type presently in use. In this vessel the deck 5 has a camber of very low angle to the horizontal and the hatch coaming 6 extends upwards from the deck a distance of at least 24 inches. The vessel also is provided with port and starboard upper wing water ballast tanks '7 of required capacity for the type of vessel.

In FIG. 2 there is shown a partial transverse section of a vessel of the same overall characteristics as the vessel illustrated in FIG. 1 but built according to the present invention. In the vessel illustrated in FIG. 2 the level of the deck 8 at the side of the vessel is the same as that of the vessel in FIG. 1. However, the juncture of the side 9 of the vessel and the deck 8 is rounded at It) and the deck 8 slopes upwards towards the centreline of the vessel at an angle of approximately 10 whereby the deck meets the level of the hatch opening 11 which is at the same level as the top of the hatch coaming 6 in FIG. 1.

The area immediately under the deck 8, on both port and starboard sides of the vessel is divided into two compartments, one compartment 12 being a water ballast tank of the same capacity as the water ballast tank 7 in FIG. 1. The other compartment 13 is a combined ventilating and piping duct.

Due to the greater slope of the deck 8 the lower surface 14 of the compartments i2 and 13 is moved upwards relative to the lower surface 15 of the tank 7 in FIG. 1 with the result that the capacity of the hold 16 is increased by twice the shaded area 17 in FIG. 2, taking into account that the capacity of the water ballast tanks 7 and 12 in both figures are the same and the addition of the ventilating and piping duct 13 is also taken into account.

The strength of vessel under deck 8 is greatly increased due to the introduction of the duct 13 and to the use of the self-trimming structure formed by the longitudinal swash bulkheads 18 and the transverse swash bulkheads 19.

A single piece steel hatch cover 20 of box girder design is mounted directly on the deck to close the square or rectangular trunk 21 formed by the swash bulkheads 18 and 19. This trunk 21 is so proportioned that the cubic capacity contained therein is 5% of the cubic capacity of the hold 16 it serves, as this is a requirement of the current regulations controlling the carriage of grain in bulk in ships on international deep sea voyages. The slope on the underside of the deck provided by the surface 14 is not less than 3% degrees in order to comply with the regulations governing self-trimming characteristics from the trunk or feeder 21 to the hold 16.

In order to secure the hatch covers 20 to the deck 8 a series of brackets 22 are welded to the deck. These brackets are spaced apart at intervals around the hatch opening 11 and have their inner facing sides slightly angled at 23 to ensure that the hatch cover will be located precisely over the jointing bar 24 which is secured to the surface of the deck around the hatch opening 11.

The hatch covers 2% are locked in place by means of the locking bars 25 mounted in the pair of lugs 26 secured on the top of the brackets 22. The locking bars 25 are each provided with a projection 27 which, when the bar is rotated about its axis, will pass through the slot 28 in the outer of the two lugs 26. In the hatch locking position of the bars 25 the projection 27 is located on the under side behind the outer of the two lugs 26 as seen in FIG. 9. The end of the bars 25 adjacent the hatch cover is secured to the brackets 28 on the sides of the hatch cover by the pins 29.

The ventilating and piping ducts 13 extend longitudinally of the vessel on both port and starboard sides of the vessel to provide ventilation to each and every hold 16. Control of ventilation to each hold is by means of the valve 30 located on the side walls 31 separating the duct 13 from the hatch trunk 21. Each valve 30 is controlled by operating gear 32 at deck level, preferably in the area between hatch covers 20 and on either side of the transverse bulkheads 33 separating the holds from each other, as seen in FIG. 6.

The duct 13, in addition to acting as a ventilation duct, accommodates the service piping 34 used for heating, fire extinguishing, deck washing, etc. The piping 34 will have branches 35 to deck level at suitable locations, as seen in FIG. 3.

In bulk oil carrier vessels it has been the practice to have a maze of deck piping. In the present application, the oil loading and unloading pipes 36 are immediately taken below deck through the deck connection 37 to a junction box 38 located within the water ballast tanks 12 and from there connection is made with the distribution pipes 39. Similarly, the oil and bilge stripping pipes 40 are taken from deck level, through the water ballast tanks 12. Above deck, the pipes 36 and 40 terminate with suitable valved shore connections at the operating platform 41.

It is understood that, while only one side of the vessel is shown in the drawings, the construction and installations shown are the same on both port and starboard sides of the vessel.

By constructing the deck area of the vessel in the manner shown in FIG. 2, the effective depth of the hull girder is increased and, by so doing, the thickness of the main deck plating as well as the longitudinals supporting the deck plating can be reduced. Therefore, for a given moulded depth in a vessel, the cargo cubic capacity can be increased without reducing the ballast capacity concomitant with a saving of about 2% of the weight of steel used in constructing the vessel.

Alternatively, the moulded depth of the vessel can be reduced and the vessel so designed will have the same ballast and cargo cubic capacity as its orthodox counterpart, but in this case, a considerable saving in the weight of steel used in constructing the vessel will accrue.

The geometry of the arrangement at the main deck is structurally very effective and much more than that which is obtained in a vessel designed in an orthodox manner where the deck has very little camber and the hatch coamings are at least 24 inches high as shown in FIG. 1. The usual stress concentrated at the hatch corners is eliminated. This has been a troublesome source of maintenance as failure often occurs in the main deck plating at the corner of the hatches.

With the very high camber on the deck any water shipped on the main deck will be shed very rapidly and with the adoption of a rounded connection between main deck stringer plate and the shear strake of the hull, deck scuppers can be completely eliminated.

The structural arrangement of the water ballast tanks and ventilating ducts on the port and starboard sides further strengthens the deck structure and, at the same time, positive control of the supply and exhaust of air to and from the cargo holds is achieved without the use of ventilators projecting above deck level.

What we claim is:

1. A deck structure for bulk cargo carrying vessels having hatch openings at deck level leading to feeder trunks for the holds of the vessel comprising a deck surface angled inwardly and upwardly from the sides of the vessel, the said deck surface defining the said hatch openings, a water ballast tank and a ventilating duct under the port and starboard deck surfaces, the lower surface of the said ballast tanks and ventilating ducts being sloped inwardly and upwardly at an angle of at least 30 degrees from the horizontal, with the said ventilating ducts being located longitudinally of the vessel adjacent the said feeder trunks, a hatch cover for each of said feeder trunks, the said hatch covers being supported on the said deck surfaces, and means to secure the said hatch covers to said deck surfaces.

2. A deck structure as set forth in claim 1 in which the said deck surface is at an angle of at least 10 degrees from the horizontal.

3. A deck structure as set forth in claim 1 in which the said angled deck surfaces increases the moulded depth of the vessel and the deck structure is correspondingly lightened by a reduction in the weight of steel required.

4. A deck structure as set forth in claim 1 in which the added cubic capacity obtained by the angled deck surfaces is added to the cubic capacity of the holds under the said water ballast tanks and ventilating ducts.

5. A deck structure as set forth in claim 1 in which the juncture of the said deck surfaces with the sides of the vessel is rounded.

6. A deck structure as set forth in claim 1 in which the said hatch covers are located on the said deck surfaces by a jointing bar secured to the deck around the periphery of the opening to the said hatch feeders.

7. A deck structure as set forth in claim 1 in which the locking means securing the said hatch covers to the deck includes a series of brackets on the said deck, and a locking bar on each of the said brackets, the said locking bars engaging with brackets on adjacent sides of the said hatch covers.

8. A deck structure as set forth in claim 7 in which the side of the said deck brackets facing the said hatch covers are angled to form guide surfaces locating the said hatch covers in place over the said feeder trunks.

9. A deck structure as set forth in claim 1 in which the said ventilating ducts on port and starboard sides of the vessel have a series of valves communicating with adjacent feeder trunks and the individual valves are controlled from above the surfaces of the deck.

10. A deck structure as set forth in claim 1 in which the said ventilating ducts form a housing for service piping and connections from the said service piping are made through the said deck.

11. A deck structure as set forth in claim 1 in which a service platform is secured to said deck at port and starboard sides of the vessel, and bulk oil loading and unloading pipes are connected through the said water ballast tanks and through the said deck adjacent the said service platforms.

No references cited.

MILTON BUCHLER, Primary Examiner. 

1. A DECK STRUCTURE FOR BULK CARGO CARRYING VESSELS HAVING HATCH OPENINGS AT DECK LEVEL LEADING TO FEEDER TRUNKS FOR THE HOLDS OF THE VESSEL COMPRISING A DECK SURFACE ANGLED INWARDLY AND UPWARDLY FROM THE SIDES OF THE VESSEL, THE SAID DECK SURFACE DEFINING THE SAID HATCH OPENINGS, A WATER BALLAST TANK AND A VENTILATING DUCT UNDER THE PORT AND STARBOARD DECK SURFACES, THE LOWER SURFACE OF THE SAID BALLAST TANKS AND VENTILATING DUCTS BEING SLOPED INWARDLY AND UPWARDLY AT AN ANGLE OF AT LEAST 30 DEGREES FROM THE HORIZONTAL, WITH THE SAID VENTILATING DUCTS BEING LOCATED LONGITUDINALLY OF THE VESSEL ADJACENT THE SAID FEEDER TRUNKS, A HATCH COVER FOR EACH OF SAID FEEDER TRUNKS, THE SAID HATCH COVERS BEING SUPPORTED ON THE SAID DECK SURFACES, AND MEANS TO SECURE THE SAID HATCH COVERS TO SAID DECK SURFACES. 